A variety of thickened aqueous scouring cleansers are known in the art and these cleansers exhibit various characteristics. For example, in U.S. Pat. Nos. 4,599,186, 4,657,692 and 4,695,394 to Choy et al. and in copending U.S. application Ser. No. 07/146,519 of Reboa et al. filed Jan. 21, 1988, thickened aqueous abrasive cleansers are disclosed which use colloidal alumina thickeners to provide abrasive cleansers which exhibit little or no syneresis over time.
Other abrasive cleansers are disclosed in U.S. Pat. No. 4,676,920 to Culshaw and published patent applications EP 126545 to Buzzaccarini and EP 216416 to Iding, which contain clay type thickeners. While these cleansers contain hydrocarbon solvents, the clay thickeners do not provide the desired properties in terms of pourability and resistance to syneresis. The disclosure of Iding indicates that including solvents in abrasive cleanser compositions contributes to the instability and syneresis of these cleansers.
Other abrasive cleansers are disclosed in U.S. Pat. Nos. 4,158,553 and 4,240,919 to Chapman; 4,396,525 and 4,129,423 to Rubin; 4,005,027 to Hartman; 4,457,856 to Mitchell; and Japanese Patent Application 60-108499 to Watanabe et al. None of the cleansers disclosed in these references provide the desired cleaning efficacy for certain applications together with the superior resistance to syneresis and the desired flowable or plastic consistency as exhibited by the Choy et al. cleansers. A specialized emulsion type skin cleaner composition for removing paint is disclosed in U.S. Pat. No. 4,508,634 to Elepano et al. as containing surfactants, solvents, an optional mild abrasive and a thickener as a protective colloid thickener for stabilizing the emulsion, which colloid can be colloidal alumina.
The disclosures of the above references are incorporated herein by reference.
In view of the above it has been found that there remains the need for a thickened aqueous abrasive cleanser having the characteristics of:
(a) having a smoothly flowable or plastic consistency, preferably pourable, and maintaining these properties over long periods of time;
(b) being stably abrasive-suspending, i.e., capable of suspending the abrasive so that it can be used without the need for prior shaking or agitation to resuspend the abrasive after standing for a period of time; and
(c) having improved cleaning efficacy for certain applications.
In the context of this invention the term "plastic" means that the cleanser is of a consistency which can undergo continuous deformation without rupture or relaxation of that consistency; the term "pourable" means that the cleanser is of a consistency which can be poured from an open container without the need for application of any force other than gravity; and the term "stably abrasive-suspending" means that the abrasive in the cleanser is and remains over long periods of time totally and fully suspended in the cleanser system, thus eliminating any need to shake, agitate or stir the cleanser before use to resuspend the abrasive mixture. In this regard, it should be noted that some liquid separation, i.e., syneresis, can occur in the cleanser, but so long as the abrasives remain fully and totally suspended, the cleanser is considered to be abrasive-suspending stable. Moreover, such liquid separation is not detrimental to dispensing or using the cleanser so long as the abrasive remains fully and totally suspended.